La. Admin. Code tit. 33 § IX-1113

Current through Register Vol. 50, No. 6, June 20, 2024

Section IX-1113 - Criteria

A. Introduction

1. Water quality criteria are elements of the water quality standards that set general and numeric limitations on the permissible amounts of a substance or other characteristics of state waters. General and numeric criteria are established to promote restoration, maintenance, and protection of state waters. A criterion for a substance represents the limits for that substance at which water quality will remain sufficient to support a designated use.

2. Water quality criteria for the waters of Louisiana are based on their present and potential uses and the existing water quality indicated by data accumulated through monitoring programs of the department and other state and federal agencies as well as universities and private sources. In some cases, available water quality and flow data are not adequate to establish criteria. Criteria in these cases are established on the basis of the best information available from water bodies that are similar in hydrology, water quality, and physical configuration.

3. General and numeric water quality criteria may be modified to take into account site-specific, local conditions. Whenever data acquired from the sources named in LAC 33:IX.1113.A.2 or other sources indicate that criteria should be modified, the department will develop and recommend revised site-specific criteria. The revised criteria will be submitted to the EPA for approval and promulgated in accordance with established procedures including, but not limited to, those in the Louisiana Administrative Procedure Act, R.S. 49:950 et seq.

B. General Criteria. Except where specifically exempted elsewhere in these standards, the general criteria shall apply at all times to the surface waters of the state, including wetlands, whether they are identified in the standards or not. General criteria specifically apply to human activities; they do not apply to naturally occurring conditions.

1. Aesthetics. The waters of the state shall be maintained in an aesthetically attractive condition and shall meet the generally accepted aesthetic qualifications. All waters shall be free from such concentrations of substances attributable to wastewater or other discharges sufficient to:

a. settle to form objectionable deposits;

b. float as debris, scum, oil, or other matter to form nuisances or to negatively impact the aesthetics;

c. result in objectionable color, odor, taste, or turbidity;

d. injure, be toxic, or produce demonstrated adverse physiological or behavioral responses in humans, animals, fish, shellfish, wildlife, or plants; or

e. produce undesirable or nuisance aquatic life.

2. Color. Water color shall not be increased to the extent that it will interfere with present usage or projected future use of the state's water bodies.

a. Waters shall be free from significant increases over natural background color levels.

b. A source of drinking water supply shall not exceed 75 color units on the platinum-cobalt scale.

c. No increases in true or apparent color shall reduce the level of light penetration below that required by desirable indigenous species of aquatic life.

3. Floating, Suspended, and Settleable Solids. There shall be no substances present in concentrations sufficient to produce distinctly visible solids or scum, nor shall there be any formation of long-term bottom deposits of slimes or sludge banks attributable to waste discharges from municipal, industrial, or other sources including agricultural practices, mining, dredging, and the exploration for and production of oil and natural gas. The administrative authority may exempt certain short-term activities permitted under Sections 402 and certified under Section 401 of the Clean Water Act, such as maintenance dredging of navigable waterways or other short-term activities determined by the state as necessary to accommodate legitimate uses or emergencies or to protect the public health and welfare.

4. Taste and Odor. Taste- and odor- producing substances in the waters of the state shall be limited to concentrations that will not interfere with the production of potable water by conventional water treatment methods or impart unpalatable flavor to food fish, shellfish, and wildlife, or result in offensive odors arising from the waters, or otherwise interfere with the designated water uses.

5. Toxic Substances. No substances shall be present in the waters of the state or the sediments underlying said waters in quantities that alone or in combination will be toxic to human, plant, or animal life or significantly increase health risks due to exposure to the substances or consumption of contaminated fish or other aquatic life. The numeric criteria (LAC 33:IX.1113.C.6) specify allowable concentrations in water for several individual toxic substances to provide protection from the toxic effects of these substances. Requirements for the protection from the toxic effects of other toxic substances not included in the numeric criteria and required under the general criteria are described in LAC 33:IX.1121.

6. Oil and Grease. Free or floating oil or grease shall not be present in quantities large enough to interfere with the designated water uses, nor shall emulsified oils be present in quantities large enough to interfere with the designated uses.

7. Foaming or Frothing Materials. Foaming or frothing materials of a persistent nature are not permitted.

8. Nutrients. The naturally occurring range of nitrogen-phosphorous ratios shall be maintained. This range shall not apply to designated intermittent streams. To establish the appropriate range of ratios and compensate for natural seasonal fluctuations, the administrative authority will use site-specific studies to establish limits for nutrients. Nutrient concentrations that produce aquatic growth to the extent that it creates a public nuisance or interferes with designated water uses shall not be added to any surface waters.

9. Turbidity

a. Turbidity other than that of natural origin shall not cause substantial visual contrast with the natural appearance of the waters of the state or impair any designated water use. Turbidity shall not significantly exceed background; background is defined as the natural condition of the water. Determination of background will be on a case-by-case basis.

b. As a guideline, maximum turbidity levels, expressed as nephelometric turbidity units (NTU), are established and shall apply for the following named water bodies and major aquatic habitat types of the state:

i. Red, Mermentau, Atchafalaya, Mississippi, and Vermilion Rivers and Bayou Teche-150 NTU;

ii. estuarine lakes, bays, bayous, and canals-50 NTU;

iii. Amite, Pearl (includes Wilson Slough and Bradley Slough), Ouachita, Sabine, Calcasieu, Tangipahoa, Tickfaw, and Tchefuncte rivers-50 NTU;

iv. freshwater lakes, reservoirs, and oxbows-25 NTU;

v. designated scenic streams and outstanding natural resource waters not specifically listed in Clauses B.9.b.i-iv of this Section-25 NTU; and

vi. for other state waters not included in Clauses B.9.b.i-v of this Section, and in water body segments where natural background turbidity exceeds the values specified in these clauses, turbidity in NTU caused by any discharges shall be restricted to the appropriate background value plus 10 percent. This shall not apply to designated intermittent streams.

c. The administrative authority may exempt for short periods certain activities permitted under Sections 404 and certified under Section 401 of the Clean Water Act, such as maintenance dredging of navigable waterways or other short-term activities that the state determines are necessary to accommodate legitimate uses or emergencies or to protect the public health and welfare.

10. Flow. The natural flow of state waters shall not be altered to such an extent that the basic character and water quality of the ecosystem are adversely affected except in situations where alterations are necessary to protect human life or property. If alterations to the natural flow are deemed necessary, all reasonable steps shall be taken to minimize the adverse impacts of such alterations. Additionally, all reasonable steps shall be taken to mitigate the adverse impacts of unavoidable alterations.

11. Radioactive Materials. Radioactive materials in the surface waters of the state designated for drinking water supply use shall not exceed levels established pursuant to the Federal Safe Drinking Water Act ( P.L. 93-523 et seq.).

12. Biological and Aquatic Community Integrity

a. The biological and community structure and function in state waters shall be maintained, protected, and restored except where not attainable and feasible as defined in LAC 33:IX.1109. This is the ideal condition of the aquatic community inhabiting the unimpaired water bodies of a specified habitat and region as measured by community structure and function. The biological integrity will be guided by the fish and wildlife propagation use designated for that particular water body. Fish and wildlife propagation uses are defined in LAC 33:IX.1111.C. The condition of these aquatic communities shall be determined from the measures of physical, chemical, and biological characteristics of each surface water body type, according to its designated use (LAC 33:IX.1123). Reference site conditions will represent naturally attainable conditions. These sites should be the least impacted and most representative of water body types. Such reference sites or segments of water bodies shall be those observed to support the greatest variety and abundance of aquatic life in the region as is expected to be or has been recorded during past surveys in natural settings essentially undisturbed by human impacts, development, or discharges. This condition shall be determined by consistent sampling and reliable measures of selected, indicative communities of animals (i.e., fish, invertebrates, etc.) and/or plants as established by the department and may be used in conjunction with acceptable chemical, physical, and microbial water quality measurements and records as deemed appropriate for this purpose.

b. Wetlands Approved for Wastewater Assimilation Projects Pursuant to the Water Quality Management Plan, Volume 3, Section 10, Permitting Guidance Document for Implementing Louisiana Surface Water Quality Standards. The biological integrity for wetlands approved for wastewater assimilation projects will be determined in accordance with procedures set forth in the Water Quality Management Plan, Volume 3 and in accordance with site-specific permit requirements. An LPDES permit identifies the requirements and conditions, including biological (or vegetative) criteria that determine compliance with the permit. Upon permit issuance, the permittee will be required to conduct ongoing physical, chemical, and biological measurements to ensure the health of the wetland. Wetland biological integrity will be guided by above-ground wetland vegetative productivity with consideration given to floral diversity. Due to effluent addition, the discharge area of a wetland shall have no more than a 20 percent reduction in the rate of total above-ground wetland productivity as compared to a reference area, unless site-specific criteria are established through the permitting process, in accordance with the Water Quality Management Plan, Volume 3. Measurements may include, but are not limited to, sampling in the discharge and reference areas. The discharge area is the area of a wetland directly affected by effluent addition. For each location, the discharge area will be defined by the volume of discharge. The reference area is the wetland area that is nearby and similar to the discharge area but that is not affected by effluent addition. Above-ground productivity is a key measurement of overall ecosystem health in the wetlands of south Louisiana. Primary productivity is dependent on a number of factors, and the methods for measurement of above-ground productivity and floral diversity are found in the current Water Quality Management Plan, Volume 3, Section 10, Permitting Guidance Document for Implementing Louisiana Surface Water Quality Standards.

13. Other Substances and Characteristics. General criteria on other substances and characteristics not specified in this Subsection will be developed as needed.

C. Numeric Criteria. Numeric criteria identified in LAC 33:IX.1123, Table 3, apply to the specified water bodies, and to their tributaries, distributaries, and interconnected streams and water bodies contained in the water management subsegment if they are not specifically named therein, unless unique chemical, physical, and/or biological conditions preclude the attainment of the criteria. In those cases, natural background levels of these conditions may be used to establish site-specific water quality criteria. Those water bodies officially approved and designated by the state and EPA as intermittent streams, man-made water bodies, or naturally dystrophic waters may be excluded from some or all numeric criteria as stated in LAC 33:IX.1109. Although naturally occurring variations in water quality may exceed criteria, water quality conditions attributed to human activities must not exceed criteria when flows are greater than or at critical conditions (as defined in LAC 33:IX.1115.C).

1. pH. The pH shall fall within the range of 6.0 to 9.0 unless natural conditions exceed this range or where otherwise specified in the table (LAC 33:IX.1123). No discharge of wastes shall cause the pH of a water body to vary by more than one pH unit within the specified pH range for the subsegment where the discharge occurs.

2. Chlorides, Sulfates, and Total Dissolved Solids. Numeric criteria for these parameters generally represent the arithmetic mean of existing data from the nearest sampling location plus three standard deviations. For estuarine and coastal marine waters subsegments in Table 3 that have no listed criteria (i.e., designated N/A), criteria will be established on a case-by-case basis using field determination of ambient conditions and the designated uses. For water bodies not specifically listed in the Numeric Criteria and Designated Uses Table, increases over background levels of chlorides, sulfates, and total dissolved solids may be permitted. Such increases will be permitted at the discretion of the department on a case-by-case basis and shall not cause in-stream concentrations to exceed 250, 250, and 500 mg/L for chlorides, sulfates, and total dissolved solids, respectively, except where a use attainability analysis indicates that higher levels will not affect the designated uses. In permitting such increases, the department shall consider their potential effects on resident biota and downstream water bodies in addition to the background conditions. Under no circumstances shall an allowed increase over background conditions cause any numeric criteria to be exceeded in any listed water body or any other general or numeric criteria to be exceeded in either listed or unlisted water bodies.

3. Dissolved Oxygen. The statewide dissolved oxygen (DO) values represent minimum criteria for the types of water specified. (That is, a level below the criterion, as opposed to above the criterion, may indicate potential impairment.) These DO criteria are designed to protect indigenous wildlife and aquatic life species associated with the aquatic environment and shall apply except in those water bodies that have ecoregional-specific or site-specific criteria, or where exempted or excluded elsewhere in these standards. DO criteria for specific state water bodies are contained in LAC 33:IX.1123. Naturally occurring variations below the criterion specified may occur for short periods (for a few hours each day). These variations reflect such natural phenomena as the reduction in photosynthetic activity and oxygen production by plants during hours of darkness. However, no waste discharge or human activity shall lower the DO concentration below the specified minimum.

a. Fresh Water. For fresh water, the DO criterion is 5 mg/L. Fresh warmwater biota is defined in LAC 33:IX.1105.

b. Estuarine Waters. For estuarine waters, the DO criterion is 4 mg/L.

c. Coastal Marine Waters (Including Nearshore Gulf of Mexico). For coastal marine waters, the DO criterion is 5 mg/L.

4. Temperature

a. The temperature criteria enumerated in the tables in most cases represent maximum values obtained from existing data. In a few cases, however, a limited number of unusually high temperatures in the range of 35° to 36°C (95-97&°F) have been deleted because these values are believed to have been recorded during conditions of unseasonably high temperatures and/or unusually low flows or water levels and therefore do not represent normal maximum temperatures.

b. The criterion consists of two parts, a temperature differential and a maximum temperature. The temperature differential represents the maximum permissible increase above ambient conditions after mixing. No additional process heat shall be added once the ambient temperature reaches the maximum temperature specified in the standards, except under natural conditions such as unusually hot, dry weather, as provided for in LAC 33:IX.1113.C.4.b.i-ii.

i. Fresh Water. The following temperature standards apply to fresh water:

(a). maximum of 2.8ºC (5°F) rise above ambient for streams and rivers;

(b). maximum of 1.7°C (3°F) rise above ambient for lakes and reservoirs; and

(c). maximum temperature of 32.2°C (90°F), except where otherwise listed in the tables. Maximum temperature may be varied on a case-by-case basis to allow for the effects of natural conditions such as unusually hot and/or dry weather.

ii. Estuarine and Coastal Waters. The following temperature standards apply to estuarine and coastal waters:

(a). maximum of 2.2°C (4°F) rise above ambient from October through May;

(b). maximum of 1.1°C (2°F) rise above ambient from June through September; and

(c). maximum temperature of 35°C (95°F), except when natural conditions elevate temperature above this level.

c. These temperature criteria shall not apply to privately owned reservoirs or to reservoirs constructed solely for industrial cooling purposes.

5. Bacteria. The applicability of bacterial criteria to a particular subsegment depends upon the use designation and geographic location of the subsegment. Criteria are established to protect water quality to support the designated uses assigned to the subsegment. The most stringent applicable fecal coliform bacterial criteria for each individual Louisiana subsegment and the applicability of enterococci bacterial criteria for coastal primary contact recreation waters are outlined in the "BAC" column of Table 3, LAC 33:IX.1123.

a. Primary Contact Recreation. The primary contact recreation criteria shall apply only during the defined recreational period of May 1 through October 31. During the nonrecreational period of November 1 through April 30, the criteria for secondary contact recreation shall apply.

i. Enterococci. The indicator, enterococci, will be used for coastal marine waters, gulf waters to the state three-mile limit, coastal bays, estuarine waters, and adjacent subsegments with recreational beach waters. The enterococci geometric mean density shall not exceed 35 colonies/100 mL and no more than 10 percent of the individual samples in the data set shall exceed 130 enterococci colonies/100 mL. The interval of time for calculating the geometric mean and the 10 percent exceedance rate may be one month or greater, but shall not exceed three months.

ii. Fecal Coliform. The indicator, fecal coliform, will be used for subsegments without applicable enterococci criteria. No more than 25 percent of the total samples collected on a monthly or near-monthly basis shall exceed a fecal coliform density of 400 colonies/100 mL.

b. Secondary Contact Recreation. No more than 25 percent of the total samples collected on a monthly or near-monthly basis shall exceed a fecal coliform density of 2,000/100 mL. This secondary contact recreation criterion shall apply year round.

c. Drinking Water Supply. No more than 30 percent of the total samples collected on a monthly or near-monthly basis shall exceed a fecal coliform density of 2,000/100 mL.

d. Oyster Propagation. The fecal coliform median shall not exceed 14 fecal coliforms per 100 mL, and not more than 10 percent of the samples shall exceed 43 fecal coliforms per 100 mL in those portions of the area most probably exposed to fecal contamination during the most unfavorable hydrographic and pollution conditions.

6. Toxic Substances. Numeric criteria for specific toxic substances are listed in Table 1.

a. Numeric criteria for specific toxic substances are mostly derived from the following publications of the Environmental Protection Agency: Water Quality Criteria, 1972 (commonly referred to as the "Blue Book"; Quality Criteria for Water, 1976 (commonly referred to as the "Red Book"; Ambient Water Quality Criteria, 1980 (EPA 440/5-80); Ambient Water Quality Criteria, 1984 (EPA 440/5-84-85); and Quality Criteria for Water, 1986-with updates (commonly referred to as the "Gold Book"). Natural background conditions, however, are also considered. These toxic substances are selected for criteria development because of their known occurrence in Louisiana waters and potential threat to attainment of designated water uses.

b. The criteria for protection of aquatic life are based on acute and chronic concentrations in fresh and marine waters (see LAC 33:IX.1105) as specified in the EPA criteria documents and are developed primarily for attainment of the fish and wildlife propagation use. Where a specific numeric criterion is not derived in EPA criteria documents, a criterion is developed by applying an appropriate application factor for acute and chronic effects to the lowest LC50 value for a representative Louisiana species. The application of either freshwater toxics criteria or marine toxics criteria in brackish waters will be determined by the average salinity of the water body (see LAC 33:IX.1105). In cases where the average salinity is 2 parts per thousand or greater and less than 10 parts per thousand, the more stringent criteria will be used unless an alternative site-specific criterion is developed (as described in EPA-822-R-02-047, November 2002).

c. Criteria for human health are derived using EPA guidelines, procedures, and equations for water bodies used as drinking water supplies and those not used as drinking water supplies. Criteria applied to water bodies designated as drinking water supplies are developed to protect that water supply for human consumption, including protection against taste and odor effects, to protect it for primary and secondary contact recreation, and to prevent contamination of fish and aquatic life consumed by humans. Criteria for water bodies not designated as drinking water supplies are developed to protect them for primary and secondary contact recreation and to prevent contamination of fish and aquatic life consumed by humans. In some cases, the maximum contaminant levels (MCLs) from the National Drinking Water Regulations, when more restrictive, are used as the criteria. For those toxic substances that are suspected or proven carcinogens, an incremental cancer risk level of 10^-6 (1 in 1,000,000) is used in deriving criteria, with the exception of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and hexachlorocyclohexane (lindane, gamma BHC), in which case 10^-5 (1 in 100,000) is used to derive the criteria.

d. Metals criteria are based on dissolved metals concentrations in ambient waters. Hardness values are averaged from two-year data compilations contained in the latest Louisiana Water Quality Data Summary or other comparable data compilations or reports. Metals criteria have been developed for both fresh and marine waters, but not brackish waters. The application of either freshwater metals criteria or marine metals criteria in brackish waters will be determined by the average salinity of the water body (see LAC 33:IX.1105). In cases where the average salinity is 2 parts per thousand or greater and less than 10 parts per thousand, the more stringent criteria will be used unless an alternative site-specific criterion is developed (as described in EPA-822-R-02-047, November 2002).

e. For purposes of criteria assessment, the most stringent criteria for each toxic substance will apply. For determination of criteria attainment in ambient water where the criteria are below the detection limit, then no detectable concentrations will be allowed. However, for dilution calculations or water quality modeling used to develop total maximum daily load and wasteload allocations, the assigned criteria, even if below the detection limit, will be used.

f. The use of clean techniques may be required to definitively assess ambient levels of some pollutants (e.g., EPA Method 1669 for metals) or to assess such pollutants when numeric or narrative water quality criteria are not being attained. Clean techniques are defined in LAC 33:IX.1105.

Table 1 Numeric Criteria for Specific Toxic Substances [In micrograms per liter tg/L)]
Toxic Substance Chemical Abstracts Service (CAS) Registry Number	Aquatic Life Protection						Human Health Protection
	Freshwater		Marine Water		Brackish Water		Drinking Water Supply1	Non-Drinking Water Supply2
	Acute	Chronic	Acute	Chronic	Acute Chronic
Aldrin309-00-2	3.00	--	1.300	--	1.300	--	4x10-5	4x10-5
Benzene 71-43-2	2,249	1,125	2,700	1,350	2,249	1,125	0.58	6.59
Benzidine 92-87-5	250	125	--	--	250	125	8x10-5	1.7x10-4
Bromodichloromethane 75-27-4	--	--	--	--	--	--	0.52	6.884
Bromoform (Tribromomethane) 75-25-2	2,930	1,465	1,790	895	1,790	895	3.9	34.7
Carbon Tetrachloride (Tetrachloromethane) 56-23-5	2,730	1,365	15,000	7,500	2,730	1,365	0.22	1.2
Chlordane 57-74-9	2.40	0.0043	0.090	0.0040	0.090	0.0040	1.9x10-4	1.9x10-4
Chloroform (Trichloromethane) 67-66-3	2,890	1,445	8,150	4,075	2,890	1,445	5.3	70
2-Chlorophenol 95-57-8	258	129	--	--	258	129	0.10	126.4
3-Chlorophenol 108-43-0	--	--	--	--	--	--	0.10	--
4-Chlorophenol 106-48-9	383	192	535	268	383	192	0.10	--
Cyanide 57-12-5	45.9	5.4	1.0	--	1.0	--	663.8	12,844
DDE 72-55-9	52.5	10.5000	0.700	0.1400	0.700	0.1400	1.9x10-4	1.9x10-4
DDT 50-29-3	1.10	0.0010	0.130	0.0010	0.130	0.0010	1.9x10-4	1.9x10-4
Dibromochloromethane 124-48-1	--	--	--	--	--	--	0.39	5.08
1,2-Dichloroethane (EDC) 107-06-2	11,800	5,900	11,300	5,650	11,300	5,650	0.36	6.8
1,1-Dichloroethylene 75-35-4	1,160	580	22,400	11,200	1,160	580	0.05	0.58
2,4-Dichlorophenoxyacetic acid (2,4-D) 94-75-7	--	--	--	--	--	--	100.00	--
2,3-Dichlorophenol 576-24-9	--	--	--	--	--	--	0.04	--
2,4-Dichlorophenol 120-83-2	202	101	--	--	202	101	0.30	232.6
2,5-Dichlorophenol 583-78-8	--	--	--	--	--	--	0.50	--
2,6-Dichlorophenol 87-65-0	--	--	--	--	--	--	0.20	--
3,4-Dichlorophenol 95-77-2	--	--	--	--	--	--	0.30	--
1, 3-Dichloropropene 542-75-6	606	303	79	39.5	79	39.5	0.33	5.51
Dieldrin 60-57-1	0.2374	0.0557	0.710	0.0019	0.2374	0.0019	5x10-5	5x10-5
Endosulfan7 115-29-7	0.22	0.0560	0.034	0.0087	0.034	0.0087	0.47	0.64
Endrin 72-20-8	0.0864	0.03575	0.037	0.0023	0.037	0.0023	0.26	0.26
Ethylbenzene 100-41-4	3,200	1,600	8,760	4,380	3,200	1,600	247	834
Heptachlor 76-44-8	0.52	0.0038	0.053	0.0036	0.053	0.0036	7x10-5	7x10-5
Hexachlorobenzene 118-74-1	--	--	--	--	--	--	2.5x10-4	2.5x10-4
Hexachlorobutadiene3 87-68-3	5.1	1.02	1.6	0.32	1.6	0.32	0.09	0.11
Hexachlorocyclohexane (gamma BHC; Lindane) 58-89-9	5.30	0.21	0.160	--	0.160	--	0.11	0.20
Methyl chloride (Chloromethane) 74-87-3	55,000	27,500	27,000	13,500	27,000	13,500	--	--
Methylene chloride (Dichloromethane) 75-09-2	19,300	9,650	25,600	12,800	19,300	9,650	4.4	87
Phenol (Total)4 108-95-2	700	350	580	290	580	290	5.00	50.0
Polychlorinated Biphenyls, Total6 (PCBs) 1336-36-3	2.00	0.0140	10.000	0.0300	2.00	0.0140	5.59x10-5	5.61x10-5
TDE (DDD) 72-54-8	0.03	0.0060	1.250	0.2500	0.03	0.0060	2.7x10-4	2.7x10-4
2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)5 1746-01-6	--	--	--	--	--	--	0.71x10-6	0.72x10-6
1,1,2,2-Tetrachloroethane 79-34-5	932	466	902	451	902	451	0.16	1.8
Tetrachloroethylene 127-18-4	1,290	645	1,020	510	1,020	510	0.65	2.5
Toluene 108-88-3	1,270	635	950	475	950	475	6,100	46,200
Toxaphene 8001-35-2	0.73	0.0002	0.210	0.0002	0.210	0.0002	2.4x10-4	2.4x10-4
1,1,1-Trichloroethane 71-55-6	5,280	2,640	3,120	1,560	3,120	1,560	200.0	--
1,1,2-Trichloroethane 79-00-5	1,800	900	--	--	1,800	900	0.56	6.9
Trichloroethylene 79-01-6	3,900	1,950	200	100	200	100	2.8	21
2-(2,4,5-Trichlorophenoxy) propionic acid (2,4,5-TP; Silvex) 93-72-1	--	--	--	--	--	--	10.00	--
Vinyl Chloride (Chloroethylene) 75-01-4	--	--	--	--	--	--	2.37x10-2	0.45

¹ Applies to surface water bodies designated as a Drinking Water Supply and also protects for primary and secondary contact recreation and fish consumption.

² Applies to surface water bodies not designated as a Drinking Water Supply and protects for primary and secondary contact recreation and fish consumption.

³ Includes Hexachloro-1,3-butadiene.

⁴ Total phenol as measured by the 4-aminoantipyrine (4AAP) method.

⁵ Advances in scientific knowledge concerning the toxicity, cancer potency, metabolism, or exposure pathways of toxic pollutants that affect the assumptions on which existing criteria are based may necessitate a revision of dioxin numerical criteria at any time. Such revisions, however, will be accomplished only after proper consideration of designated water uses. Any proposed revision will be consistent with state and federal regulations.

⁶ Total refers to the sum of the Aroclor analyses: PCB-1016 (CAS 12674-11-2), PCB-1221 (CAS 11104-28-2), PCB-1232 (CAS 11141-16-5), PCB-1242 (CAS 53469-21-9), PCB-1248 (CAS 12672-29-6), PCB-1254 (CAS 11097-69-1), and PCB-1260 (CAS 11096-82-5).

⁷ Endosulfan is the sum of Endosulfan [ALPHA] (959-98-8) and Endosulfan [BETA] (33213-65-9).

Table 1A Numeric Criteria for Metals and Inorganics [In micrograms per liter (µg/L) or parts per billion (ppb)]
Toxic Substance Chemical Abstracts Service (CAS) Registry Number	Aquatic Life Protection			Human Health Protection Drinking Water Supplyc
	Freshwater	Marine Water	Brackish Waterd
Arsenica 7440-38-2	Acute: 339.8 Chronic: 150	Acute: 69 Chronic: 36	Acute: 69 Chronic: 36	10
Cadmiuma,b 7440-43-9	Acute: e (1.1280[ln(hardness)] - 1.6774) x CF1 Chronic: e (0.7852[ln(hardness)] - 3.4900) x CF2	Acute: 45 Chronic: 10	Acute: * Chronic: *	10
Chromium III (Tri)a,b 16065-83-1	Acute: e (0.8190[In(hardness) ] + 3.6880) x 0.316 Chronic: e (0.8190[ln(hardness)] + 1.5610) x 0.86	Acute: 515 Chronic: 103	Acute: * Chronic: *	50
Chromium VI (Hex)a 18540-29-9	Acute: 16 Chronic: 11	Acute: 1,100 Chronic: 50	Acute: 16 Chronic: 11	50
Coppera,b,h 7440-50-8	Acute: e (0.9422[ln(hardness)] - 1.3844) x 0.960 Chronic: e (0.8545[ln(hardness)] - 1.3860) x 0.960	Acute: 3.63 Chronic: 3.63	Acute: * Chronic: *	1,000
Leada,b 7439-92-1	Acute: e (1.2730[ln(hardness)] - 1.4600) x CF3 Chronic: e (1.2730[ln(hardness)] - 4.7050) x CF3	Acute: 209 Chronic: 8.08	Acute: * Chronic: *	50
Mercury 7439-97-6	Acute: 2.04e Chronic: 0.012f	Acute: 2e Chronic: 0.025f	Acute: 2e Chronic: 0.012f	2.0
Nickela,b 7440-02-0	Acute: e (0.8460[ln(hardness)] + 3.3612) x 0.998 Chronic: e (0.8460[ln(hardness)] + 1.1645) x 0.997	Acute: 74 Chronic: 8.2	Acute: * Chronic: *	--
Zinca,b 7440-66-6	Acute: e (0.8473[ln(hardness)] + 0.8604) x 0.978 Chronic: e (0.8473[ln(hardness)] + 0.7614) x 0.986	Acute: 90 Chronic: 81	Acute: * Chronic: *	5,000
Conversion Factor (CF)	CF1 calculated as: 1.136672-[ln (hardness)(0.041838)] CF2 calculated as: 1.101672-[ln (hardness)(0.041838)] CF3 calculated as: 1.46203-[ln (hardness)(0.145712)]

* For hardness-dependent criteria, values are calculated using average hardness (mg/L CaCO3) from two-year data compilations contained in the latest Louisiana Water Quality Data Summary or other comparable data compilations or reports, as described in LAC 33:IX.1113.C.6.

^a Freshwater and saltwater metals criteria are expressed in terms of the dissolved metal in the water column. The standard was calculated by multiplying the previous water quality criteria by a conversion factor. The conversion factor represents the EPA-recommended conversion factors found in EPA-822-R-02-047, November 2002.

^b Hardness-dependent criteria for freshwater are based on the natural logarithm formulas multiplied by conversion factors for acute and chronic protection. The minimum and maximum hardness values used for criteria calculation are 25 mg/L and 400 mg/L CaCO3, as specified in 40 CFR 131.36.

^c Applies to surface water bodies designated as drinking water supply and also protects for primary and secondary contact recreation and fish consumption.

^d According to LAC 33:IX.1113.C.6.d, the most stringent criteria (freshwater or marine) will be used.

^e Conversion factor is from: Office of Water Policy and Technical Guidance on Interpretation and Implementation of Aquatic Life Metals Criteria, October 1, 1993. Factors were expressed to two decimal places.

^f It is not appropriate to apply a conversion factor to the chronic value for mercury since it is based on mercury residues in aquatic organisms rather than toxicity.

^g For temperature (T, in °C) and pH dependent criteria, values are calculated using the temperature and pH measured at the time of sampling in coordination with the ambient water quality monitoring program.

^h Upon request the administrative authority may grant the use of the Biotic Ligand Model for deriving site-specific copper criteria utilizing the procedures identified in EPAs Aquatic Life Ambient Freshwater Quality Criteria - Copper (2007), EPA-822-R-07-001. Site-specific criteria derived using the Biotic Ligand Model are new and revised water quality standards that require EPA review under section 303(c) of the Clean Water Act.

La. Admin. Code tit. 33, § IX-1113

Promulgated by the Department of Environmental Quality, Office of Water Resources, LR 10:745 (October 1984), amended LR 15:738 (September 1989), LR 17:264 (March 1991), LR 17:967 (October 1991), repromulgated LR 17:1083 (November 1991), amended LR 20:883 (August 1994), LR 24:688 (April 1998), amended by the Office of Environmental Assessment, Environmental Planning Division, LR 25:2402 (December 1999), LR 26:2547 (November 2000), LR 27:289 (March 2001), LR 30:1474 (July 2004), amended by the Office of the Secretary, Legal Affairs Division, LR 33:457 (March 2007), LR 33:829 (May 2007), LR 35:446 (March 2009), Amended by the Office of the Secretary, Legal Division, LR 42736 (5/1/2016), Amended by the Office of the Secretary, Legal Affairs and Criminal Investigations Division, LR 451188 (9/1/2019), Amended LR 461550 (11/1/2020), Amended LR 481498 (6/1/2022, Amended by the Office of the Secretary, Legal Affairs Division LR 491553 (9/1/2023).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2074(B)(1).